back and forth 来来回回；反复
例句：
He walked back and forth in the room, thinking about the problem.
他在屋里来回走动，思考着问题。
Don't say this back and forth, I know how to do.
不要反复说这个，我知道该怎么做。
A:Please don't go back and forth, I'm doing my homework.
请不要来回走动，我在写作业。
B:Oh, I'm sorry, I didn't notice that you were doing your homework.
哦，对不起，我没注意到你在写作业。
背景音乐：
Before You Break My Heart — Stevie Hoang
